2015-08-02T22:35:09ZBiochemical composition and performance of Atlantic cod (Gadus morhua L.) eggs and larvae obtained from farmed and wild broodstockshttp://idl-bnc.idrc.ca:8080/dspace/handle/10625/52021
Title: Biochemical composition and performance of Atlantic cod (Gadus morhua L.) eggs and larvae obtained from farmed and wild broodstocks
Authors: Ceccon Lanes, Carlos Frederico; Tilahun Bizuayehu, Teshome; Bolla, Sylvie; Martins, Camila; de Oliveira Fernandes, Jorge Manuel
Abstract: Farming of Atlantic cod, Gadus morhua L., has been facing several challenges lately. Biological issues such as differences in egg quality and lack of high quality larvae are considered as prominent limiting factors. The aim of this study was to compare fertilization and hatching rates, incidence of malformed larvae at hatching, larval viability (high-salinity stress and starvation tolerance tests) and the biochemical profile (proteins, amino acids, lipids, fatty acids and minerals) between eggs produced from wild and farmed broodstocks. Twenty-five batches of eggs from farmed broodstock (FB) and 27 egg batches from wild broodstock (WB) were collected during the reproductive season. Fertilization and hatching rates were significantly higher in WB group (91±3% and 86±3%, respectively) than in FB (75±3% and 66±3%, respectively). In highsalinity stress test, WB larvae survived for a significantly longer time than FB larvae. No differences between egg batches from the two broodstocks were observed in starvation tolerance tests, incidence of malformed larvae at hatching, as well as in the total content of proteins, lipids, fatty acids, zinc, and calcium concentrations. Regarding fatty acids, FB eggs had significantly higher levels of C16:0, C18:0, C18:2n−6, C18:3n−3, C18:3n−6, C20:4n−6, C20n:5n−3, C22:5n−3 and C22:5n−6, whereas WB eggs had significantly higher levels of C14:0, C16:1n−7, C18:4n−3, C20:4n−3, C22:6n−3 and C24:1n−9. As for the amino acid profile, WB eggs had significantly higher levels of aspartic acid, serine, glycine, threonine, taurine and leucine, while FB eggs had significantly higher levels of proline, tryptophan, phenylalanine and arginine. The concentrations of minerals such as copper and phosphorus were significantly higher in WB eggs, whereas in FB eggs iron concentration was significantly higher. Overall, the biological parameters indicated that egg and larvae originating from WB were of superior quality than those from FB. The information on the biochemical profile may be useful in improving the quality of broodstock feeds for Atlantic cod.2012-01-01T00:00:00ZMortality, bioaccumulation and physiological responses in juvenile freshwater mussels (Lampsilis siliquoidea) chronically exposed to copperhttp://idl-bnc.idrc.ca:8080/dspace/handle/10625/52020
Title: Mortality, bioaccumulation and physiological responses in juvenile freshwater mussels (Lampsilis siliquoidea) chronically exposed to copper
Authors: Jorge, Marianna B.; Loro, Vania L.; Bianchini, Adalto; Wood, Chris M.; Gillis, Patricia L.
Abstract: Several studies have indicated that the early life stages of freshwater mussels are among the most sensitive aquatic organisms to inorganic chemicals, including copper. However, little is known about the toxic mode of action and sub-lethal effects of copper exposure in this group of imperiled animals. In this study, the physiological effects of long-term copper exposure (survival, growth, copper bioaccumulation, whole-body ion content, oxygen consumption, filtration rate, ATPase activities, and biomarkers of oxidative stress) were evaluated in juvenile (6 month old) mussels (Lampsilis siliquoidea). The mussels' recovery capacity and their ability to withstand further acute copper challenge were also evaluated in secondary experiments following the 28 day exposure by assessing survival, copper bioaccumulation and whole-body ion content. Mussels chronically exposed to 2 and 12 μg Cu/L showed significantly higher mortality than those held under control conditions (mortality 20.9, 69.9 and 12.5%, respectively), indicating that juvenile L. siliquoidea is underprotected by the U.S. Environmental Protection Agency (USEPA) biotic ligand model (BLM)-derived chronic water quality criteria (WQC) (2.18 μg Cu/L) and the hardness-derived USEPA WQC (12.16 μg Cu/L). Soft tissue copper burden increased equally for both copper exposures, suggesting that chronic toxicity is not associated with copper bioaccumulation. Several physiological disturbances were also observed during chronic copper exposure. Most relevant was a decrease in whole-body sodium content paralleled by an inhibition of Na(+) K(+)-ATPase activity, indicating a metal-induced ionoregulatory disturbance. Filtration and oxygen consumption rates were also affected. Redox parameters (reactive oxygen production, antioxidant capacity against peroxyl radicals, glutathione-S-transferase (GST) activity, and glutathione (GSH) concentration) did not show clear responses, but membrane damage as lipid peroxidation (LPO) was observed in both copper exposures. Mussels previously held in control conditions or pre-exposed to 2 μg dissolved Cu/L were able to maintain their ionic homeostasis and did not experience mortality after the 4-d recovery period. In contrast, those previously exposed to 12 μg dissolved Cu/L exhibited 50% mortality indicating that they had already reached a 'point of no return'. Pre-exposure to copper did not influence mussel response to the copper challenge test. As observed for the chronic exposure, mortality of mussels held in the absence of copper and submitted to the challenge test was also associated with an ionoregulatory disturbance. These results indicate that ionoregulatory disruption in freshwater mussels chronically exposed to copper is the main mechanism of toxicity and that redox parameters do not appear to be useful as indicators of sub-lethal copper toxicity in these animals.2013-01-01T00:00:00ZEstimation of zooplankton secondary production in estuarine waters : Comparison between the enzymatic (chitobiase) method and mathematical models using crustaceanshttp://idl-bnc.idrc.ca:8080/dspace/handle/10625/52019
Title: Estimation of zooplankton secondary production in estuarine waters : Comparison between the enzymatic (chitobiase) method and mathematical models using crustaceans
Authors: Ramos Avila, Tatiana; Abel de Souza Machado, Anderson; Bianchini, Adalto
Abstract: Sampling was seasonally performed in the Patos Lagoon estuary (Rio Grande, RS, Southern Brazil) to estimate zooplankton biomass and production comparing values obtained using an enzymatic (chitobiase) method and the traditional mathematical models based on growth. Comparison of data obtained from zooplankton samples collected with 90 and 200-␣m mesh nets showed that net selectivity in␣uences the estimation of zooplankton biomass and production. Furthermore, it showed differential results for dominance of taxa and proportions of developmental stages in samples. Differences among samples collected at the different sites in the same season were observed using either the mathematical models or the enzymatic method. The two different approaches were also able to detect the seasonal variation in production. In a broad view, data obtained using the chitobiase method showed a similar pattern of zooplankton production compared to those obtained with the traditional mathematical models based on growth. However, values estimated using the enzymatic method were systematically higher than those obtained with the mathematical models. Maxi- mum total production values were estimated as 12.5, 9.2 and 7.9 mg C m␣ 3 day␣ 1 for the “chitobiase method”, “Huntley model”, and “Hirst model”, respectively. Considering all sampling sites and seasons, the magnitude of this difference corresponded to 1.95 and 2.49 mg C m␣ 3 day␣ 1 for the “Huntley model” and the “Hirst model”, respectively. These ␣ndings indicate the reliability of the enzymatic method in estimating crustacean production also in estuarine environments of changing salinity, as previously demonstrated for marine waters. In addition, the use of this method is more practical and comparatively less time-consuming and cheaper than the use of the mathematical models based on growth.2012-01-01T00:00:00ZCopper effects on key metabolic enzymes and mitochondrial membrane potential in gills of the estuarine crab Neohelice granulata at different salinitieshttp://idl-bnc.idrc.ca:8080/dspace/handle/10625/52018
Title: Copper effects on key metabolic enzymes and mitochondrial membrane potential in gills of the estuarine crab Neohelice granulata at different salinities
Authors: Machado Lauer, Mariana; Bento de Oliveira, Camila; Inocencio Yano, Natalia Lie; Bianchini, Adalto
Abstract: The estuarine crab Neohelice granulata was exposed (96 h) to a sublethal copper concentration under two different physiological conditions (hyperosmoregulating crabs: 2 ppt salinity, 1 mg Cu/L; isosmotic crabs: 30 ppt salinity, 5 mg Cu/L). After exposure, gills (anterior and posterior) were dissected and activities of enzymes involved in glycolysis (hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase), Krebs cycle (citrate synthase), and mitochondrial electron transport chain (cytochrome c oxidase) were analyzed. Membrane potential of mitochondria isolated from anterior and posterior gill cells was also evaluated. In anterior gills of crabs acclimated to 2 ppt salinity, copper exposure inhibited hexokinase, phosphofructokinase, pyruvate kinase, and citrate synthase activity, increased lactate dehydrogenase activity, and reduced the mitochondrial membrane potential. In posterior gills, copper inhibited hexokinase and pyruvate kinase activity, and increased citrate synthase activity. In anterior gills of crabs acclimated to 30 ppt salinity, copper exposure inhibited phosphofructokinase and citrate synthase activity, and increased hexokinase activity. In posterior gills, copper inhibited phosphofructokinase and pyruvate kinase activity, and increased hexokinase and lactate dehydrogenase activity. Copper did not affect cytochrome c oxidase activity in either anterior or posterior gills of crabs acclimated to 2 and 30 ppt salinity. These findings indicate that exposure to a sublethal copper concentration affects the activity of enzymes involved in glycolysis and Krebs cycle, especially in anterior (respiratory) gills of hyperosmoregulating crabs. Changes observed indicate a switch from aerobic to anaerobic metabolism, characterizing a situation of functional hypoxia. In this case, reduced mitochondrial membrane potential would suggest a decrease in ATP production. Although gills of isosmotic crabs were also affected by copper exposure, changes observed suggest no impact in the overall tissue ATP production. Also, findings suggest that copper exposure would stimulate the pentose phosphate pathway to support the antioxidant system requirements. Although N. granulata is very tolerant to copper, acute exposure to this metal can disrupt the energy balance by affecting biochemical systems involved in carbohydrate metabolism.2012-01-01T00:00:00ZAssessment of water quality in coastal waters of Fernando de Noronha, Brazil : biomarker analyses in Amphistegina lessoniihttp://idl-bnc.idrc.ca:8080/dspace/handle/10625/52017
Title: Assessment of water quality in coastal waters of Fernando de Noronha, Brazil : biomarker analyses in Amphistegina lessonii
Authors: de Freitas Prazeres, Martina; Eslava Martins, Samantha; Bianchini, Adalto
Abstract: Symbiont-bearing foraminiferal assemblages from reef
environments have proven useful as ecological indicators for
water quality. Studies with other organisms have utilized
cellular biomarkers to elucidate mechanisms of stress
response. Our goal was to combine these approaches,
focusing on populations of the symbiont-bearing foraminifer
Amphistegina lessonii from Fernando de Noronha Archipelago
(northeastern Brazil). Reef-rubble samples containing A.
lessonii were collected at five sampling sites on the leeward
side of the main island. Three sites were located inside and
two outside the Fernando de Noronha National Marine Park
(FNNMP) area. Foraminifers were evaluated regarding their
density, degree of bleaching, antioxidant capacity against
peroxyl radicals (ACAP), lipid peroxidation (LPO), protein
carbonylation (PC), and concentrations of metallothioneinlike
proteins (MTs). Densities of A. lessonii were lower at
sites located outside the FNNMP, compared with those inside
the FNNMP, where the maximum average was 159±29
individuals/100 cm2. In individuals from sites located outside
FNNMP, bleaching frequency reached 25%, though ,2%; at
FNNMP sites (,1.8%;). ACAP was higher (two-fold) in
individuals collected at the FNNMP sites, which showed
lower LPO and PC levels. MTs concentration did not differ
significantly among sites. Zinc, copper, and lead concentrations
were very high at stations located outside FNNMP.
Dissolved organic carbon concentration was high at all
sampling sites. Redundancy analysis revealed a strong
correlation between biomarkers and water quality among
sampling sites. These results show that the biomarker
approach would be effective in identifying impacted areas
and underlying causes, providing a reliable diagnostic for
environment health.2012-01-01T00:00:00Z